Investor Warren Buffett speaks during the 'United State of Women Summit' at the Washington Convention Center in Washington, DC, last June. / SAUL LOEB/AFP/Getty Images

Shares of Warren Buffett’s firm Berkshire Hathaway soared 20% in 2016, helping to boost Buffett’s personal fortune by $12.3 billion – more than any other billionaire in the United States. The Oracle of Omaha is now worth $74.2 billion, enough to make him the 2nd-richest person in the world (behind only Bill Gates, who is worth $84 billion), according to FORBES' calculations.

Buffett was a firm supporter of Hillary Clinton during the 2016 presidential campaign, but he scored most of his gains this year, some $7.8 billion, after she lost the election in November. Buffett's fortune rose $3.6 billion in the two days following the election alone when Berkshire Hathaway stock jumped 6%.

It wasn’t all a smooth ride for Berkshire Hathaway. Buffett’s firm is the largest shareholder of bank Wells Fargo, which was fined $185 million in September for opening millions of accounts without customers’ permission. Federal officials opened investigations, members of Congress berated the bank, and CEO John Stumpf ultimately left his position in October. Berkshire shares dropped 4% in the month after authorities fined Wells Fargo.

Berkshire Hathaway stock began to make a comeback on Nov. 4, when the company released its third-quarter results. Buffett’s firm reported $11.4 billion in quarterly revenues, up 8% from the previous year. Shares edged upwards, gaining 3% from Nov. 4 to Nov. 8, slightly outpacing the market’s overall rise heading into Election Day. Once Donald Trump won, Berkshire took off along with the rest of the stock market.

Fracking titan Harold Hamm is $8.8 billion richer now compared to December 31, 2015, the second biggest dollar gain of anyone in America. Shares of his oil giant Continental Resources soared 136% thanks to the rising price of crude oil. The Texas oilman has ridden oil’s boom and bust cycles for years. He gained more than $13 billion from 2010 to 2014, lost more than $13 billion by March 2016, then regained most of it in the last nine months. Today he is worth $15.1 billion, FORBES calculates.

Amazon CEO Jeff Bezos also had a big year, adding $6.6 billion to his coffers as Amazon shares rose. And gambling tycoon Sheldon Adelson gained $5.6 billion. Still, no one could match Buffett, who would be even richer if he had not given away $2.9 billion worth of Berkshire stock in July. Six years ago Buffett and his friend Bill Gates created the Giving Pledge, a commitment by billionaires around the world to donate over half of their money. For his part, the Omaha investor has promised to donate more than 99% of his fortune. So far, he has given away more than $28.5 billion.